U.S. Pat. No. 4,911,454 discloses a hydraulic sealing ring which fits between a shaft and a surrounding bore in which the shaft extends. The sealing ring comprises an annular seal formed of an elastic rubber material and a stiffening ring formed of a hard plastic material. The annular seal has a radially inner lip which sealingly engages the shaft, and has a radially outer surface which sealingly engages the bore in which the shaft extends. The stiffening ring supports the annular seal when the annular seal is pressed against the stiffening ring between the shaft and the bore. The annular seal and the stiffening ring are not bonded to each other, but are instead held together by a mechanical interlock.